Technical Abstract:
The economic loss of ammonia (NH3) volatilization from chemical N fertilizers applied to farmlands worldwide is 11.6 billion US dollars per year. The economic impact of negative environmental effects resulted from NH3 volatilization, i.e., formation of potent greenhouse gas (N2O) and PM2.5, is difficult to estimate but enormous. The Shannon’s Information Theory was applied to the data collecteddd from our previous study using either ammonium sulfate [(NH4)2SO4], ammonium nitrate (NH4NO3), potassium nitrate (KNO3), or urea applied to four agricultural soils, i.e., Biscayne Marl Soil (BMS) and Krome Gravelly Loam (KGL) from Florida and Quincy Fine Sand (QFS) and Warden Silt Loam (WSL) from Washington, at two soil water regimes (20% and 80% field capacity, FC) and incubated at either 11, 20, or 29°C. Shannon rate (Rs g N ha-1 bit-1) was defined as N-loss per unit area per Shannon entropy via NH3 volatilization from the fertilized soils. The results showed that the Rs values across the four soils were 3-fold greater at 20% FC than that at 80% FC soil water regime. The BMS and KGL soils depicted similar R
values, i.e., 2362.5 and 2378.9, while those for the QFS and WSL soils were only 1079.0 and 851.1 g N ha-1 bit-1, respectively. The Rs values were 4178.6, 2863.3, 1502.3, and 21.7 g N ha-1 bit-1 for urea, (NH4)2SO4, NH4NO3 and KNO3, respectively. The environmental friendliness of either the tested soils, fertilizers, or soil water regimes ,etc. were based on the Rs values, discussed.